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The aim of this study was to determine the liquid-liquid equilibrium data for a ternary system of water, ethyl acetate and oil from the microalgae Scenedesmus obliquus at 298.15, 308.15, and 318.15 K. The potential of the ternary system was also investigated for the selective extraction of free fatty acids and neutral lipids from crude microalgae oil. The equilibrium data were obtained using a model oil formulated from a mixture of refined vegetable oils, with a fatty acid profile analogous to the dark and opaque algae oil. The experimental equilibrium curves and tie lines were provided as a function of temperature for a free fatty acid content of 2%, 20% and 40% (w/w). The free fatty acids in the model oil migrated preferentially to the ethyl acetate-rich phase in each of the systems under study, with extraction efficiencies ranging from 79.4% to 97.1%. However, the extraction efficiencies for the neutral lipids were lower (51.5–70.1%), indicating the preferential extraction of free fatty acids. The distribution coefficients of neutral lipids (1.06–2.34) and free fatty acids (3.85–33.2) were determined in order to better understand the selectivity of the green solvent, ethyl acetate, in the purification of crude oil from algae. The selectivity values varied from 1.84 to 28.6, indicating that the solvent was effective in concentrating neutral lipids and free fatty acids in the ethyl acetate-rich phase. The increase in free fatty acid content therefore reduced the partition coefficient for neutral lipids, improving its selectivity, and making it possible to concentrate this lipid class by liquid-liquid separation with ethyl acetate. [ABSTRACT FROM AUTHOR]

In this work we determined the position of the separation boundary, measured the interfacial tension and densities of equilibrium phases in the ternary system "water-ethanol-cyclohexane" at temperatures of 277.15 K and 293.15 K. The phase equilibria for these conditions were simulated by the molecular dynamics method. It is found that molecular dynamics reproduces well the initial decrease in interfacial tension but agrees poorly with experimental data on the density and compositions of the water phase. The observed crystallization of the organic phase at 277.15 K may be useful for rapid phase separation in lipid extraction. [ABSTRACT FROM AUTHOR]

One of the most accepted hypothesis to explain the anomalous behavior of water is the presence of a critical point between two liquids, the liquid–liquid critical point (LLCP), buried within the deep supercooled regime. Unfortunately, such hypothesis is hard to be experimentally confirmed due to fast freezing. Here, we show that the TIP4P/Ice water potential shifted by 400 bar can reproduce with unprecedented accuracy the experimental isothermal compressibility of water and its liquid equation of state for a wide pressure and temperature range. We find, both by extrapolation of response function maxima and by a Maxwell construction, that the location of the model LLCP is consistent with previous calculations. According to the pressure shift needed to recover the experimental behavior of supercooled water, we estimate the experimental LLCP to be located around 1250 bar and 195 K. We use the model to estimate the ice nucleation rate (J) in the vicinity of the hypothesized LLCP experimental location and obtain J = 1024 m−3 s−1. Thereby, experiments where the ratio between the cooling rate and the sample volume is equal or larger than the estimated nucleation rate could probe liquid–liquid equilibrium before freezing. Such conditions are not accessible in common experiments with microdroplets cooled at a few kelvin per second, but they could be, for instance, using nanodroplets of around 50 nm radius observed in a millisecond timescale. [ABSTRACT FROM AUTHOR]

This study is interested in the sorption of Fe(III) and/or La(III) from liquid solutions by modified Melia Azedarach zinc oxide (MAZO) sorbent. MAZO was fabricated by impregnation of ZnO on the external surface of thermally treated Melia Azedarach fruits. The prepared sorbent was characterised by different analytical tools; FT-IR, XRD, TGA&DTA, EDX, SEM, and TEM. Sorption data showed equilibrium time (60 min). The distribution coefficients as a function of pH have a separation factor $${\alpha ^{La}}_{Fe}$$ α La Fe (77) at pH 2.4. Capacity has the values 66.8 & 37.42 mgg−1 for Fe(III) & La(III) respectively. Finally, column data reveal that Fe(III) and/or La(III) can be loaded and separated from the crude phosphoric acid and synthetic waste using different concentrations of HNO3 as eluent. The investigation evidenced that MAZO is suitable for the recovery of Fe(III) and/or La(III) from liquid waste. [ABSTRACT FROM AUTHOR]

Although the system water + n-propanol + toluene is important for research and industry, its liquid–liquid equilibria LLE are scarcely covered in literature, with no thermodynamic modeling reported using typical equations of state or activity coefficient models. The current work addresses this gap by presenting the equilibria of the system at 20°C and atmospheric pressure. That includes the binodal curve and twelve tie lines covering the entire miscibility gap, whereby the compositions of the conjugate phases are determined using high-precision refractive index measurements. The quality of the data is verified by applying the techniques of conjugate lines and mass balances, whereas it is shown that empirical correlations cannot be used for that purpose. Three different methods to extrapolate the critical point are then employed and, using the more reliable one, that point is located and added to the dataset. Further thermodynamic correlation of the data is conducted using the activity coefficient models, UNIQUAC and NRTL. While the former did not perform well, the latter was able to model the LLE and adapt to temperature changes. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the liquid–liquid equilibrium (LLE) behavior of sesame fatty acid ethyl ester (FAEE) and methyl ester (FAME) in combination with glycerol and the co-solvents ethanol and methanol. FAEE and FAME were produced through the transesterification of mechanically extracted and purified sesame oil, using potassium hydroxide (KOH) as a homogeneous base catalyst. The reactions were conducted in ethanol and methanol to produce FAEE and FAME, respectively. Post-reaction, the products were separated and purified, followed by an analysis of the LLE behavior at 313.15 K and 323.15 K under atmospheric pressure (101.3 kPa). The experimental process for the miscibility analysis utilized a jacketed glass cell adapted for this study. Miscibility limits or binodal curves were determined using the turbidity-point method. Tie lines were constructed by preparing mixtures of known concentrations within the two-phase region, which allowed the phases to separate after agitation. Samples from both phases were analyzed to determine their composition. This study revealed that higher temperatures promoted greater phase separation and enhanced the biodiesel purification process. The NRTL model effectively correlated the activity coefficients with the experimental data, showing good agreement, with a root-mean-square deviation of 3.5%. Additionally, the data quality was validated using Marcilla’s method, which yielded an R2 value close to 1. Attraction factors and distribution coefficients were also calculated to evaluate the efficiency of the co-solvents as extraction agents. The findings indicated higher selectivity for methanol than for ethanol, with varying degrees of distribution among the co-solvents. These results offer significant insights into enhancing biodiesel production processes by considering the effects of co-solvents on the LLE properties of mixtures, ultimately contributing to more efficient and cost-effective biodiesel production. [ABSTRACT FROM AUTHOR]

In order to separate phenol from water, at 101.3 kPa, the liquid-liquid equilibria (LLE) data of water + phenol + solvents (trichloromethane, isoamyl alcohol) were obtained at 298.15, 303.15, and 313.15 K. The ability of the extractant to extract phenol from water was evaluated by the distribution coefficient (D) and selectivity coefficient (S). The Bachman and Hand equations were used to verify the reliability of the LLE data with the linear coefficient was greater than 0.98%. The LLE data was correlated with the NRTL and UNIQUAC models to obtain a binary interaction parameter with an RMSD not greater than 0.36%. [ABSTRACT FROM AUTHOR]

Methyl acrylate has a wide range of uses, but the production process usually produces aqueous by-products. In this study, four commonly used alcohols (1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol) were selected as extractants to explore the liquid–liquid extraction behavior of water + methyl acrylate + extractants. Through the analysis of partition coefficient (D) and separation coefficient (S), it is found that the data of all systems are greater than 1, indicating that all four alkyl alcohols can well separate methyl acrylate from aqueous solution, and 1-octanol is the best. In addition, the consistency between the binary interaction parameters of regression and tie-line data was tested using Matlab tools, proving that the obtained parameters have good consistency. [ABSTRACT FROM AUTHOR]

In this study, a method for separating isopropanol from wastewater using hydrophobic deep eutectic solvents (DESs) synthesized from terpenes and capric acid was proposed. The distribution coefficient and selectivity value of isopropanol (IPA) in the solvents were determined by liquid–liquid extraction experiments, and the extraction performances of the solvents at different molar ratios and temperatures were studied. From the perspective of molecular dynamics simulations, the experimental results were verified by mechanism analysis, the contribution of hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs) to the selective separation of isopropanol was explained. The interaction energies, radial distribution functions, normal density distribution, and mean square deviations between the atoms were used to analyze the interactions between the components of the DESs and IPA/water. It was observed that the DESs have a good extraction effect on IPA, which verifies the good application prospects of DESs in wastewater solutions containing alcohol compounds. [ABSTRACT FROM AUTHOR]

Increasing concern about climate change and the need to reduce dependence on fossil fuels have driven the search for more sustainable energy alternatives. One way to reduce emissions is by adding oxygenated compounds such as biodiesel and alcohols to diesel fuel. However, this can lead to phase separation between the fuels and have serious consequences for engine performance. In this context, the present study aimed to evaluate the effect of ethanol content on the miscibility of components in mixtures containing ethanol + biodiesel + diesel through the study of liquid-liquid equilibrium. The results from ternary phase diagrams revealed that the amount of water present in ethanol has a significant effect on the miscibility of the mixture components, with larger biphasic regions observed in systems with lower ethanol content. For the 95% ethanol diagram, the reliability of experimental data on equilibrium lines was assessed through the Othmer-Tobias and Hand correlations, which showed correlation coefficients (R²) of 0.996 and 0.995, respectively. The results obtained from the NRTL and UNIQUAC thermodynamic models demonstrated excellent agreement with the experimental data, with a deviation of only 1.78 and 0.78% for the NRTL and UNIQUAC models. [ABSTRACT FROM AUTHOR]

The equilibrium silica liquid–liquid interface between the high-density liquid (HDL) phase and the low-density liquid (LDL) phase is examined using molecular-dynamics simulation. The structure, thermodynamics, and dynamics within the interfacial region are characterized in detail and compared with previous studies on the liquid–liquid phase transition (LLPT) in bulk silica, as well as traditional crystal–melt interfaces. We find that the silica HDL–LDL interface exhibits a spatial fragile-to-strong transition across the interface. Calculations of dynamics properties reveal three types of dynamical heterogeneity hybridizing within the silica HDL–LDL interface. We also observe that as the interface is traversed from HDL to LDL, the Si/O coordination number ratio jumps to an unexpectedly large value, defining a thin region of the interface where HDL and LDL exhibit significant mixing. In addition, the LLPT phase coexistence is interpreted in the framework of the traditional thermodynamics of alloys and phase equilibria. [ABSTRACT FROM AUTHOR]

Abatract: The objective of this study is to assess the efficacy of two specific ionic liquids, namely 1-ethyl-3-methylimidazolium dicyanamide and 1-benzyl-3-methylimidazolium dicyanamide, as potential substitutes for conventional solvents in the removal of sulfur compounds from model fuels, a common challenge in the petroleum industry. This research examines the liquid-liquid equilibria (LLE) data of three different ternary systems to evaluate the ability of these ionic liquids to extract thiophene from aliphatic hydrocarbons, n-dodecane or n-hexadecane, simulating kerosene and diesel fuels, respectively. Liquid-liquid equilibrium measurements were conducted for these mixtures at a temperature of 313.15 K and atmospheric pressure to determine the solvents thiophene distribution coefficients and selectivities. Additionally, the impact of the length of the paraffin alkyl chain was examined. The experimental data were found to conform to the thermodynamic NRTL model, with an average root mean square deviation (rmsd) of 0.2165. Both ionic liquids efficiently extracted thiophene from n-dodecane and n-hexadecane, highlighting their potential for producing ultra-low sulfur fuels.

The wettability of polymers is usually inadequate to ensure the appropriate spreading of polar liquids and thus enable the required adhesion of coatings. A standard ecologically benign method for increasing the polymer wettability is a brief treatment with a non-equilibrium plasma rich in reactive oxygen species and predominantly neutral oxygen atoms in the ground electronic state. The evolution of the surface wettability of selected aromatic polymers was investigated by water droplet contact angles deposited immediately after exposing polymer samples to fluxes of oxygen atoms between 3 × 1020 and 1 × 1023 m−2s−1. The treatment time varied between 0.01 and 1000 s. The wettability evolution versus the O-atom fluence for all aromatic polymers followed similar behavior regardless of the flux of O atoms or the type of polymer. In the range of fluences between approximately 5 × 1020 and 5 × 1023 m−2, the water contact angle decreased exponentially with increasing fluence and dropped to 1/e of the initial value after receiving the fluence close to 5 × 1022 m−2. [ABSTRACT FROM AUTHOR]

Conventional distillation methods cannot effectively separate the components of an azeotropic mixture since both phases have the same composition, thereby preventing further separation. Additional techniques such as pressure swing distillation or distillation with entrainers are often employed to overcome this limitation and achieve separation. The aim of this investigation was to select the most effective method for separating n-hexane and ethanol. The feasibility of three methods was analyzed: reduced pressure distillation, extractive distillation, and liquid–liquid extraction. The mutual solubility of n-hexane and prepared deep eutectic solvents (DESs) (nine hydrophilic: choline chloride with glycerol, ethylene glycol, or carboxylic acid (malic, citric, glycolic); tetramethylammonium chloride with glycolic acid; lactic acid with glycerol; K2CO3 with glycerol or ethylene glycol; two hydrophobic: menthol with decanoic or dodecanoic acid) was experimentally determined. Extraction experiments were conducted to test the solubility of DESs in the feed mixture. The effect of changing DES-to-feed mass ratio was further investigated with choline chloride–glycerol (1:2). The same DES and both hydrophobic DESs were able to increase the relative volatility and enhance the separation of ethanol and n-hexane. Based on the obtained results, extraction was selected as the most effective method for the separation of n-hexane and ethanol. [ABSTRACT FROM AUTHOR]

Having a comprehensive knowledge of phase equilibrium is advantageous for industrial simulation and design of chemical processes. For further acquisition of primary data to facilitate the separation and purification of waste oil biodiesel systems, a liquid–liquid equilibrium (LLE) tank is deployed for the ternary system of waste oil biodiesel + methanol + glycerin, thereby enhancing the precision and efficiency of the process. The phase equilibrium system was constructed under the influence of atmospheric pressure at precise temperatures of 303.15 K, 313.15 K, and 323.15 K. The equilibrium components of each substance were analyzed by employing high-temperature gas chromatography, a sophisticated analytical method that enables the identification and quantification of individual components of a sample. Moreover, the ternary liquid–liquid equilibrium data were correlated by implementing the NRTL and UNIQUAC activity coefficient models. Subsequently, the binary interaction parameters of the ternary system were derived by conducting regression analysis. The experimental data demonstrated that the presence of lower methanol content in the system resulted in nearly immiscible biodiesel and glycerol phases, which ultimately facilitated the separation of biodiesel and glycerol. Conversely, with the increase in methanol content, the mutual solubility of biodiesel and glycerol was observed to increase gradually. The results showed that the calculated values of the NRTL and UNIQUAC models aligned well with the experimental values. The root-mean-square deviations of the NRTL and UNIQUAC models at 313.15 K were 2.76% and 3.56%, respectively. [ABSTRACT FROM AUTHOR]

The experimental liquid-liquid equilibrium (LLE) data for the extraction of methanol from aqueous solution using mixed solvents (toluene + cyclohexanol) at 291.15 K and atmospheric pressure at the ratios (0, 0.25, 0.4, 0.6, 0.8, 1) was studied. The values of the solvent ratio 0 and 1 led us to study the liquid-liquid equilibrium of the ternary systems (water/methanol/cyclohexanol) and (water/methanol/toluene). The compositions of the coexisting phases were determined by the cloud point method. The tie line data for ternary and quaternary systems were correlated by NRTL model. The Othmer-Tobias and Hand correlations were also tested, to verify the reliability of the experimental tie lines data. The separation factor and the distribution coefficient were calculated from the experimental data to evaluate the effect of using mixed solvents. It was found that the ratio M = 0.4 is the best suited for the liquid-liquid extraction of methanol from water. [ABSTRACT FROM AUTHOR]

The efficient separation of aromatics/alkanes is important for the efficient utilization of fossil resources. Based on the influence of ionic symmetry structure on the polarity, melting point, interaction force, and spatial site resistance of ionic liquid solvents, a protonic ionic liquid with anionic and cationic double symmetry structure [DMI][FeCl4] was designed and synthesized for alkane de‐aromatization process, which enhances the Van der Waals forces dominated by dispersed forces with aromatics, and thus enhances the extraction efficiency of aromatic. For the binary system of dodecane/decalin + tetralin/1‐methylnaphthalene, and two simulated oil systems of six‐component straight‐sun diesel fuel and hydrofinishing LCO, [DMI][FeCl4] showed excellent de‐aromatization effects. The selectivity coefficients for monocyclic and bicyclic aromatic hydrocarbons can reach 150 and 480, respectively. When used in the de‐aromatization process of real oils, about 40% of the aromatic hydrocarbons can be removed by a single extraction using a 1:5 O/A ratio. [ABSTRACT FROM AUTHOR]

The paper shows the expediency of supplementing the balance simplex method by calculating the number of free variables of separation flowsheets containing recycle flows. The need to determine and set the free variables that provide lower energy consumption when calculating the material balance of flowsheets with recycling is justified. The problem of material balance multivariance is illustrated, and ways to solve it are shown with the example of separation flowsheets for two ternary mixtures: n-butanol + water + toluene and n-butanol + butyl acetate + water. Separation flowsheets containing three distillation columns and a liquid–liquid separator are proposed for both systems. The dependence of the recycle flow values and the energy consumption of distillation columns and separation flowsheets on the selection and setting of values of free variables in solving the balance problem is shown. The dependence of energy consumption on the composition of the original mixture is studied for an n-butanol + butyl acetate + water system. Recommendations for setting free variables for flowsheets of the separation of ternary mixtures with three binary (and one ternary) azeotropes are formulated. The technique of highlighting the region of separation flowsheet operability is illustrated. The column operating parameters that ensure the production of products of a given quality with minimal energy consumption are determined. It is shown that with the incorrect selection and setting of variables (during balance task solvation), the energy consumption for mixture separation can be overestimated by more than 40%. [ABSTRACT FROM AUTHOR]

When considering the usage of ionic liquids (ILs) for reactions and separations involving non-polar or weak-polar hydrocarbons, the knowledge of the mutual solubility behaviors of ILs and hydrocarbons is of the utmost importance. In this work, taking four typical C6-hydrocarbons namely benzene, cyclohexene, cyclohexane, and hexane as representatives, the mutual solubility of ILs and non-polar or weak-polar hydrocarbons are systematically studied based on the COSMO-RS model. The reliability of COSMO-RS for these systems is first evaluated by comparing experimental and predicted hydrocarbon-in-IL activity coefficient at infinite dilution and binary/ternary liquid-liquid equilibria of related systems. Then, the mutual solubility of the four hydrocarbons and 13,650 ILs (composed by 210 cations and 65 anions) are predicted. The effect of different IL structural characteristics including alkyl chain length, cation family/symmetry/functional group, and anion on the IL-hydrocarbon mutual solubility behaviors are further analyzed by the analyses of interaction energy and screen charge distribution. The mutual solubility databases and the structural effects identified thereon could provide useful guidance for IL selection in related applications. [ABSTRACT FROM AUTHOR]

Molecular dynamics (MD) simulations were performed to determine the three-phase coexistence line of sI methane hydrates. The MD simulations were carried out at four different pressures (4, 10, 40, and 100 MPa) by using the direct phase coexistence method. In current simulations, water was described by either TIP4P/Ice or "optimal" point charge (OPC) models and methane was described as a simple Lennard-Jones interaction site. Lorentz–Berthelot (LB) combining rules were used to calculate the parameters of the cross interactions. For the OPC model, positive deviations from the energetic LB rule were also considered based on the solubility of methane in water. For the TIP4P/Ice water model, the obtained three phase coexistence temperatures showed good agreement with experiment data at higher pressures, which is consistent with previous predictions. For the OPC water model, simulations using the classic and the modified LB parameters both showed negative deviations to the experimental values. Our results also indicated that the deviation of the T3 prediction by the OPC model was not closely correlated with the predicted melting point of ice. At 4 MPa, the modified OPC model showed a better prediction of hydrate equilibrium temperature, even better than the prediction by TIP4P/Ice. Considering the relatively higher accuracy in biomolecular MD of the OPC model, it is suggested that this model may have a better performance in hydrate MD simulations of biomolecule-based additives. [ABSTRACT FROM AUTHOR]

Classical thermodynamic methods often encounter challenges when applied to model the intricate behavior of liquid-liquid equilibria within biofuel production systems. To overcome these limitations, Artificial Neural Networks (ANNs) have emerged as a promising avenue for effectively describing such complex systems. This study developed and evaluated ANNs to predict the behavior of two key systems, glycerol+ethanol+CO 2 and glycerol+methanol+CO 2 , employing diverse configurations and parameters. A total of 516 distinct ANNs were methodically crafted and evaluated. Notably, the Cascade Feed-Forward architecture exhibited optimal performance in predicting the CO 2 +glycerol+ethanol system, while the Elman networks excelled in predicting the CO 2 +glycerol+methanol system. The optimized ANNs were subsequently benchmarked against analogous systems in the literature by applying established thermodynamic equations. Remarkably, the results of this research work underscore the superior predictive accuracy of the ANN approach, yielding significantly diminished error values. Specifically, the mean squared error (MSE) values of 0.1283 and 0.0892 were achieved for the methanol and ethanol systems, respectively. This study contributes substantively by showcasing the ability of ANNs to surpass classical methods for accurate prediction within the intricate domain of biofuel production systems. [Display omitted] • Optimal ANNs predict CO 2 + glycerol systems accurately (MSE: 0.13; 0.09). • Predict results with a relatively small number of iterations. • ANNs offer efficiency and versatility in complex system predictions. [ABSTRACT FROM AUTHOR]

An integrated experimental and thermodynamic modeling investigation of the phase equilibria in the PbO–NiO–SiO2 system in air and also in equilibrium with liquid metal has been undertaken to better characterize the chemical reactions taking place in the Ni‐containing Pb processing slags. New experimental phase equilibria data at 720°C–1740°C were obtained for this system using high‐temperature equilibration of synthetic mixtures with predetermined compositions in sealed silica ampoules or in Au/Pt–Ir foils, a rapid quenching technique, and electron probe x‐ray microanalysis of the equilibrated phase compositions. Phase equilibria and liquidus isotherms in the quartz/tridymite/cristobalite (SiO2), olivine (Ni2SiO4), monoxide (NiO), Ni‐barysilite (Pb8NiSi6O21), massicot (PbO), and di‐lead silicate (Pb2SiO4) primary phase fields were revealed and the extent of the high‐SiO2 two‐liquid immiscibility gap in equilibrium with cristobalite was determined. New experimental data were used in the development of a thermodynamic database describing this ternary system. Also, modeling revision of the NiO–SiO2 binary system was conducted, resulting in a smaller miscibility gap in ternary systems that was closer to the experimental results. [ABSTRACT FROM AUTHOR]

Despite offering remarkable advantages as solvents, double salt ionic liquids (DSILs) have been scarcely studied for extractive dearomatization from hydrocarbons as well as many other applications, thus urging a theoretical guidance method. In this work, a systematic framework combining the rational screening validation and mechanistic analysis is proposed for tailoring DSILs for the o‐xylene/n‐octane separation. From an initial pool of commercially available ionic liquids (ILs), key thermodynamic properties of paired DSILs are predicted by COSMO‐RS while their important physical properties are estimated from those of corresponding parent ILs (retrieved from experimental database or predicted by a deep learning model). Promising DSILs are tested by liquid–liquid equilibrium experiments, wherein the effect of ion ratio is also evaluated. The mechanism underlying the tunability of DSIL thermodynamic properties is disclosed by quantum chemistry calculation and molecular dynamics simulation. This work can be a valuable reference for guiding the design of DSILs for diverse applications. [ABSTRACT FROM AUTHOR]

In the present study, we studied the effectiveness of the water‐soluble polymer polyethylene glycol methyl ether 350 (PEG ME‐350) on the extraction of nitrogen‐containing heterocyclic compounds—quinoline and indole—from n‐hexane. The dependences of the quantitative characteristics of the extraction of N‐compounds on the contact time of the phases, the content of PEG ME‐350 in the n‐hexane–water system, the initial concentration of nitrogen‐containing heterocyclic compounds in the organic phase, and the volumetric ratio of the phases were obtained. It has been established that PEG ME‐350 is an effective extractant in the process of stepwise extraction of quinoline and indole, and the mechanisms of their extraction have also been proposed and proven. The results can be further used in the purification of light hydrocarbon fractions from nitrogen‐containing heterocyclic compounds. [ABSTRACT FROM AUTHOR]

In order to effectively practice the Aqueous Lignin Purification with Hot Agents (ALPHA) process for lignin purification and fractionation, the temperatures and feed compositions where regions of liquid–liquid equilibrium (LLE) exist must be identified. To this end, pseudo‐ternary phase diagrams for the lignin–acetic acid–water system were mapped out at 45–95 °C and various solvent: feed lignin mass ratios (S : F). For a given temperature, the accompanying SL (solid–liquid), SLL (solid–liquid–liquid), and one‐phase regions were also located. For the first time, ALPHA using acetic acid (AcOH)–water solution was applied to a lignin recovered via the commercial LignoBoost process. In addition to determining tie‐line compositions for the two regions of LLE that were discovered, the distribution of lignin and key impurities (the latter can negatively impact lignin performance for materials applications) between the two liquid phases was also measured. As a representative example, lignin isolated in the lignin‐rich phase was reduced 7x in metals and 4x in polysaccharides by using ALPHA with a feed solvent composition of 50–55 % AcOH and an S : F of 6 : 1, with said lignin being obtained at a yield of 50–70 % of the feed lignin and having a molecular weight triple that of the feed. [ABSTRACT FROM AUTHOR]

1,4-butanediol (BDO) can be produced by the biotechnological route; however, the process of separating BDO from fermentation broths is energy-intensive due to its high boiling point and complete miscibility with water, which motivates to propose separation routes that involve energy savings. Therefore, an aqueous two-phase system was proposed for the recovery of BDO from aqueous solutions using K 2 CO 3 as a phase-forming agent, without the need for additional solvent. The liquid-liquid equilibrium of the system K 2 CO 3 + BDO + H 2 O was determined at 25 °C and the ENRTL-RK thermodynamic model was used to correlate the experimental data and perform the process simulation in Aspen Plus. Applying this technique, it was possible to concentrate a BDO solution from 12.5% w/w to 84.58% w/w in a liquid-liquid extraction stage with a recovery of 99.59%. Therefore, K 2 CO 3 is a dehydrating agent that could be used for the recovery of BDO obtained by fermentation. [Display omitted] • The liquid-liquid equilibrium of the ternary system K 2 CO 3 +BDO+H 2 O was determined. • K 2 CO 3 is a dehydrating agent for the recovery of BDO from aqueous solutions. • Increasing the amount of K 2 CO 3 improves purity, recovery and partition coefficient. • Salt recovery represents the main consumption of energy. [ABSTRACT FROM AUTHOR]

The mutual immiscibility of glycerol and free fatty acids limits glycerolysis, a reaction capable of upgrading waste‐derived oils. In the present work, the liquid‐liquid phase equilibrium data for the glycerol‐water‐oleic acid and glycerol‐monoolein‐oleic acid ternary systems were determined experimentally and compared with predictions of the UNIFAC‐LLE and COSMO‐SAC models. Monoolein was found to affect the glycerol solubility in oleic acid strongly. None of the models investigated adequately determined phase equilibria for the glycerol‐monoolein‐oleic acid system. COSMO‐SAC predictions showed the best trend for glycerol solubility in the fatty phase. For the glycerol‐water‐oleic acid system, UNIFAC‐LLE predictions were in good agreement with experimental data. [ABSTRACT FROM AUTHOR]

Separation of carboxylic acids from downstream is a bottleneck in the chemical industry since it takes nearly 30–50 % of the overall production cost. In view of this, an attempt was made for the extraction of acrylic acid from aqueous solution with tri‐n‐butyl phosphate dissolved in organic diluents like benzene, toluene, xylene, hexane, and petroleum ether. The results are explained in terms of distribution coefficient (σ), extraction efficacy (η%), equilibrium complexation constant (Kε), loading ratio (ϕ), and coextraction of water. At lower concentration of acrylic acid and higher concentration of tri‐n‐butyl phosphate for the acrylic acid‐tri‐n‐butyl phosphate system, maximum extraction efficacy and distribution coefficient for benzene was found as 88.60 % and 7.772, respectively. Coextraction of water in the extract phase and law of mass action were discussed, too. Diffusivity of acrylic acid to the interface of extract (organic) and raffinate (aqueous) phases was calculated using the Wilke‐Chang equation and Reddy‐Doraiswamy equation. In view of designing a continuous extraction column, the number of theoretical stages and minimum solvent‐to‐feed ratio were also determined. [ABSTRACT FROM AUTHOR]

A multicomponent Flory‐Huggins model is implemented and utilized to describe the liquid–liquid equilibrium phenomenon in mixtures of polypropylene and xylene, in the context of the well‐known xylene solubles (XS) test. The XS experiment is a common procedure in many polymer laboratories, used to determine the percentage of xylene solubles in samples of polypropylene, which provides an approximate measure of the atactic and oligomeric chains. Despite the importance of the test, the literature lacks a thermodynamic perspective regarding the description of this extraction phenomenon. In the present study, the Flory‐Huggins interaction parameter is adjusted in a multicomponent framework to ensure that equilibrium chain length distributions calculated with the proposed model best match experimental distributions. It is shown that the experimental data obtained from XS analyses can be accurately fitted by the proposed model and that the estimated Flory‐Huggins interaction parameter is more sensitive to the polymer average molar mass than to the degree of tacticity, when a particular catalyst is considered. [ABSTRACT FROM AUTHOR]

The CaO–MgO–Al2O3 system is one of the most fundamental oxide systems for various metallurgical and ceramic applications. The composition of slag co-saturated by CaO and MgO is important for accurate slag control in the secondary refining steelmaking process. In the present study, the co-saturated slag compositions at 1550 °C to 1650 °C were determined from the classical quenching experiment with Pt crucible. Based on the new experimental data and available data in literature, thermodynamic re-assessment of the CaO–MgO–Al2O3 system was carried out and new phase diagrams were calculated in the ternary system. [ABSTRACT FROM AUTHOR]

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Ternary phase diagrams in liquid-liquid equilibrium, for the water-ethanol-ethyl acetate system, were calculated and the results presented in rectangular and triangular diagrams. Initially, the thermodynamical background and the conditions of equilibrium are presented, involving the equality of activities and the mass balance condition. From this system of equations, the Rachford-Rice equation is deduced, transforming the problem of eight equations into a problem of one equation with one unknown. The Non-Random-Two-Liquid model was adopted to calculate activity coefficients, but other models can be easily adapted. An algorithm is presented to calculate the equilibrium compositions of this ternary system, together with numerical results. The theoretical-experimental comparison is in fair agreement, showing the robustness and simplicity of the Rachford-Rice equations. The material presented here is accessible to undergraduate students.

This study aimed to investigate the liquid–liquid equilibrium (LLE) behavior of sesame fatty acid ethyl ester (FAEE) and methyl ester (FAME) in combination with glycerol and the co-solvents ethanol and methanol. FAEE and FAME were produced through the transesterification of mechanically extracted and purified sesame oil, using potassium hydroxide (KOH) as a homogeneous base catalyst. The reactions were conducted in ethanol and methanol to produce FAEE and FAME, respectively. Post-reaction, the products were separated and purified, followed by an analysis of the LLE behavior at 313.15 K and 323.15 K under atmospheric pressure (101.3 kPa). The experimental process for the miscibility analysis utilized a jacketed glass cell adapted for this study. Miscibility limits or binodal curves were determined using the turbidity-point method. Tie lines were constructed by preparing mixtures of known concentrations within the two-phase region, which allowed the phases to separate after agitation. Samples from both phases were analyzed to determine their composition. This study revealed that higher temperatures promoted greater phase separation and enhanced the biodiesel purification process. The NRTL model effectively correlated the activity coefficients with the experimental data, showing good agreement, with a root-mean-square deviation of 3.5%. Additionally, the data quality was validated using Marcilla’s method, which yielded an R2 value close to 1. Attraction factors and distribution coefficients were also calculated to evaluate the efficiency of the co-solvents as extraction agents. The findings indicated higher selectivity for methanol than for ethanol, with varying degrees of distribution among the co-solvents. These results offer significant insights into enhancing biodiesel production processes by considering the effects of co-solvents on the LLE properties of mixtures, ultimately contributing to more efficient and cost-effective biodiesel production.

Ionic liquids (ILs) have been proposed as extractants for separation of metals, including rare earth elements. In particular, protonated betaine bis(trifluoromethylsulfonyl)imide ([HBet][TFSI]) exhibits liquid–liquid phase behavior with water that can be tuned by complexation with various metals. Here we show that previously undetected neutral zwitterionic betaine formed during the IL synthesis can affect the phase behaviour. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs), have been recognized as effective materials for the extraction of different compounds. In this study, the performance of a novel hydrophobic DES was evaluated for the extraction of phenol from aqueous solutions. Octanoic and dodecanoic fatty acid precursors with a definite molar ratio of 3:1, respectively, were used for the DES having a low melting point of 8.3 °C. The purity and stability of the product were confirmed via characterizing by FTIR, 1H and 13C NMR methods. The liquid–liquid equilibrium of the water + phenol + DES ternary system at different temperatures of 293.2, 298.2 and 308.2 K was accordingly studied through cloud point titration method and refractive index measurement. Interestingly, the important parameters of the solute distribution coefficient and the separation factor were, respectively, within the high levels of (6.8321–9.7787) and (895.76–2770.17), indicating the amazing capability of the DES. Reasonably, both of these parameters decreased with temperature. The NRTL and UNIQUAC thermodynamic models were employed to reproduce the obtained tie-lines and to determine the interaction parameters at each temperature. The low level root mean square deviations for the mentioned models were, respectively, within (0.0014–0.0027) and (0.0045–0.0063); confirming satisfactorily agreement with the experimental data. [ABSTRACT FROM AUTHOR]

According to the process of extraction distillation in aromatics extraction unit: the separation processes of extraction distillation column, non-aromatic distillation column and solvent recovery column were studied using PRO/II simulation software・ The models of vapor-liquid equilibrium and liquid-liquid equilibrium for highly non-ideal system were selected・ The activity coefficient equation parameters and infirdte dilution activity coefficient required for the phase equilibrium calculation model of several important components, such as aromatics, olefins and solvents, were imported through manual external input, the calculation range of the models of vapor-liquid phase equilibrium was widened・ The simulation modules of column equipment, such as extraction distillation column was estabilished・ A complete simulation software package for the extraction distillation process of aromatics extraction urdt was established・ After comparison, the deviation between the simulation results and the reference data was acceptable・ The software package can be used for the engineering design of the aromatics extraction unit. The variation of infinite dilution activity coefficient of alkanes, olefins, cycloalkanes and aromatics in sulfolane with various factors was summarized. [ABSTRACT FROM AUTHOR]

In this work, we compared the shape of a binodal curve in the ternary systems "water – methanol – chloroform", "water – methanol – dichloromethane", "water – tert-butanol – toluene", and "water – 2-butoxyethanol – toluene" in the vicinity of the liquid-liquid critical point (LLCP). We have shown that different approaches to characterize the binodal shape are not equivalent for real ternary systems. The preferred approach involves the calculation of distances based on the tangent to the LLCP and the perpendicular lines to the points on the binodal. The variability in the apparent degree of the binodal curve is revealed, contrary to the known literature. [ABSTRACT FROM AUTHOR]

The purpose of this research is to characterize and explore the feasibility of deep eutectic solvent‐based aqueous two‐phase system (DES‐ATPS) for its potential application in the extraction and purification of anthocyanins. Various combinations and molar ratios of DES using choline chloride as hydrogen bond acceptor (HBA) and butanediol (BDO), ethylene glycol (EG), and lactic acid (LA) as hydrogen bond donor (HBD) were synthesized, screened, and investigated on its physicochemical properties. The binodal phase diagrams were developed as basis for the ATPS development. It was noted that LA‐based natural deep eutectic solvents (NADES) were highly polar and likely to enhance the solubility of anthocyanin in DES. Regardless, the simple molecular structure and low viscosity of EG‐ and BDO‐based DES enhanced the solubility of anthocyanin and recorded a monomeric anthocyanin content ranging from 10.52 ± 0.78 mg cyanidin‐3‐glucoside/g at 40°C and 10.78 ± 0.84 mg cyanidin‐3‐glucoside/g at 30°C, respectively. Lastly, the liquid–liquid equilibrium binodal curves were developed and ChCl:1,3‐BDO (1:4) and ChCl:1,4‐BDO (1:4) exhibited excellent phase‐forming ability, thus concluding its excellent potential for anthocyanin extraction through ATPS. [ABSTRACT FROM AUTHOR]

The process of perfluoro(7-methylbicyclo[4.3.0]nonane) (MBCN) purification from an industrial mixture of decalin or naphthalene fluorination products is considered. According to experimental data, distillation separation allows us to concentrate MBCN to a fraction with the target-component content of more than 0.950 wt. fr., after which the process efficiency begins to decrease quickly; upon reaching a concentration of 0.975 wt. fr., separation practically breaks down (the value of the separation coefficient → 1). The process of purification of MBCN by the method of heteroazeotropic distillation using acetone (Aс) as a separating agent is proposed, the process being realized on a batch semi-industrial distillation column. The method makes it possible to intensify significantly the final stage of purification and to increase the MBCN content from 0.950 to more than 0.998 wt. fr., the mass fraction of the enriched fraction sampling comprises more than 0.85 of the load and the product yield being above 88%. The values of the separation coefficients between the distillate and the bottom product and the coefficients of enrichment for the target and impurity components are given; for the MBСN–Aс binary system, data on the liquid–liquid phase equilibrium and heteroazeotrope characteristics are determined. [ABSTRACT FROM AUTHOR]

Using the analytical option of the Origin Lab computer program, the analytical dependences of the liquidus temperature on the composition for the PbTe-Bi2Te3, PbTe-Sb2Te3, Bi2Te3-Sb2Te3 boundary systems of the PbTe-Bi2Te3-Sb2Te3 ternary system were determined. Based on these dependencies and thermal analysis data of the ternary system, the analytical model of the temperature-composite dependence of the crystallization surfaces of PbTe, Sb2Te3, Bi2Te3 compounds and PbBi2Te54, PbBi54Te7, PbBi6Te10 phases in the PbTe-Bi2Te3-Sb2Te3 system was determined. The resulting equations made it possible to visualize the phase diagram of the PbTe-Bi2Te3-Sb2Te3 system from the side of the PbTe-Bi2Te3 in 3D coordinates. The analytical model of the phase diagram of the PbTe-Bi2Te3-Sb2Te3 system allowed constructing a threedimensional image of equilibrium phases from different angles, to obtain two-dimensional projections and to tabulate the coordinates of the phase diagram [ABSTRACT FROM AUTHOR]

Liquid-liquid equilibrium (LLE) data for the ternary system, Aniline + Toluene + Water, was measured at different temperatures of 298.15 K, 313.15 K and 323.15 K under atmospheric pressure with the help of High-Performance Liquid Chromatography (HPLC) analysis and Karl-Fischer technique. The efficiency of Toluene to extract Aniline from aqueous phase was then quantified in terms of the distribution coefficient and separation factor based on the tie line data. The system showed very good separation ability quantified in terms of high values of distribution factor (average around 7) and separation factors (as high as 1000). The experimental tie line data was verified by Hand and Othmer-Tobias equations. The LLE data was also correlated using NRTL and UNIQUAC models and both of them were able to represent the behavior of the system accurately when tested against experimental results. Toluene has been demonstrated to be very efficient to extract Aniline from reaction mixture, which is typically a by-product in hydrogenation of nitrobenzene, a process commercially used to produce p-Aminophenol in industry. [ABSTRACT FROM AUTHOR]

In this work, a critical evaluation of all available phase diagrams and thermodynamic data for the As–Cd, As–Zn and As–Cd–Zn systems has been performed and thermodynamic assessments over the whole composition ranges are presented using the CALPHAD method. To predict thermodynamic properties and phase equilibria for these systems, the Modified Quasichemical Model for short range ordering was used for the liquid phase and the Compound Energy Formalism was used for the solid solutions. The optimized binary systems are in good agreement with existing experimental data. Within the ternary system predicted phase equilibria, the ZnAs 2 - CdAs 2 and Zn 3 As 2 - Cd 3 As 2 sections are in good agreement with the experimental data. Also, the eutectic temperature is accurately optimized for ZnAs 2 - Cd 3 As 2 and Zn 3 As 2 - CdAs 2 . However, the calculated liquidus of these two joins are less satisfactory compared to the experimental data. This is most likely due to the polymerization behavior of arsenic and its multivalence, which is not considered by the model used in this work. [ABSTRACT FROM AUTHOR]

It has recently been shown that the TIP4P/Ice model of water can be studied numerically in metastable equilibrium at and below its liquid–liquid critical temperature. We report here simulations along a subcritical isotherm, for which two liquid states with the same pressure and temperature but different density can be equilibrated. This allows for a clear visualization of the structural changes taking place across the transition. We specifically focus on how the topological properties of the H-bond network change across the liquid–liquid transition. Our results demonstrate that the structure of the high-density liquid, characterized by the existence of interstitial molecules and commonly explained in terms of the collapse of the second neighbor shell, actually originates from the folding back of long rings, bringing pairs of molecules separated by several hydrogen-bonds close by in space. [ABSTRACT FROM AUTHOR]

Conventional distillation methods cannot effectively separate the components of an azeotropic mixture since both phases have the same composition, thereby preventing further separation. Additional techniques such as pressure swing distillation or distillation with entrainers are often employed to overcome this limitation and achieve separation. The aim of this investigation was to select the most effective method for separating n-hexane and ethanol. The feasibility of three methods was analyzed: reduced pressure distillation, extractive distillation, and liquid–liquid extraction. The mutual solubility of n-hexane and prepared deep eutectic solvents (DESs) (nine hydrophilic: choline chloride with glycerol, ethylene glycol, or carboxylic acid (malic, citric, glycolic); tetramethylammonium chloride with glycolic acid; lactic acid with glycerol; K2CO3 with glycerol or ethylene glycol; two hydrophobic: menthol with decanoic or dodecanoic acid) was experimentally determined. Extraction experiments were conducted to test the solubility of DESs in the feed mixture. The effect of changing DES-to-feed mass ratio was further investigated with choline chloride–glycerol (1:2). The same DES and both hydrophobic DESs were able to increase the relative volatility and enhance the separation of ethanol and n-hexane. Based on the obtained results, extraction was selected as the most effective method for the separation of n-hexane and ethanol.

Having a comprehensive knowledge of phase equilibrium is advantageous for industrial simulation and design of chemical processes. For further acquisition of primary data to facilitate the separation and purification of waste oil biodiesel systems, a liquid–liquid equilibrium (LLE) tank is deployed for the ternary system of waste oil biodiesel + methanol + glycerin, thereby enhancing the precision and efficiency of the process. The phase equilibrium system was constructed under the influence of atmospheric pressure at precise temperatures of 303.15 K, 313.15 K, and 323.15 K. The equilibrium components of each substance were analyzed by employing high-temperature gas chromatography, a sophisticated analytical method that enables the identification and quantification of individual components of a sample. Moreover, the ternary liquid–liquid equilibrium data were correlated by implementing the NRTL and UNIQUAC activity coefficient models. Subsequently, the binary interaction parameters of the ternary system were derived by conducting regression analysis. The experimental data demonstrated that the presence of lower methanol content in the system resulted in nearly immiscible biodiesel and glycerol phases, which ultimately facilitated the separation of biodiesel and glycerol. Conversely, with the increase in methanol content, the mutual solubility of biodiesel and glycerol was observed to increase gradually. The results showed that the calculated values of the NRTL and UNIQUAC models aligned well with the experimental values. The root-mean-square deviations of the NRTL and UNIQUAC models at 313.15 K were 2.76% and 3.56%, respectively.